The left-handed versus right-handed asymmetry of our living world—a “chirality” seen most often in mirror-image architectures of many biomolecules—is one of its most striking features yet one of the most difficult to comprehend. Immersing chiral molecules within chiral environments is an important route to asymmetry, exploited in chemistry for synthesizing and separating chiral molecules according to their handedness. However, the thermodynamics of such a route is not well understood. In a new publication in Physical Review X, we theoretically explore this thermodynamics using a chiral nanoparticle diffusing within a chiral optical light field.

Demonstrating how chiral degrees of freedom can turn into genuine thermodynamics parameters yields a new and rich playground for further exploring chiral light-matter interactions with far-reaching consequences. To that end, we build a stochastic optomechanical model to reveal and control the mechanisms of asymmetry. One central result of our work is to highlight the thermodynamical significance of the coupling between the chirality of the particle and the chirality of the light field.

Our results pave the way to new opportunities in the context of chiral sensing, recognition, and separation of chiral objects at the nanoscale that should now be implemented experimentally and exploited.

Our perspective about chemistry under vibrational strong coupling just appeared in the Journal of the American Chemical Society. We expose the fundamentals of light-matter strong coupling, the recent advancements in vibro-polaritonic chemistry and the numerous perspectives offered by this new approach, that is easy to implement and thus promising for future exploration of light-matter interactions in molecular and material sciences.

A new publication, presenting results obtained in collaboration with National Taiwan Normal University and Shanghai Jiao Tong University just appeared in ACS Photonics. We achieved ultrafast polarization of light by combining the anisotropic optical nonlinear response of ITO at its epsilon-near-zero region with a plasmonic nanoantennas array, at their polarization-sensitive resonance. A rotation of light polarization of more than 30° is obtained together with a π/7 phase change within 600fs. Such a large anisotropic nonlinearity is a significant step towards the realization of ultrafast polarization modulators and phase retarders.

A new publication just appeared in Angewandte Chemie International Edition , in collaboration with IPCMS, Strasbourg, and University of Heidelberg. We studied the self-assembly of a conjugated polymer under vibrational strong coupling. It appeared under electron microcopy that the supramolecular morphology is totally different from that observed in the absence of strong coupling. Morever the self-assembly kinetics is modified and depends on which bond of the solvent is coupled.

A review entitled “Manipulating matter by strong-coupling to vacuum field” just appeared in Science. It has been written by Pr T.W. Ebbesen in collaboration with Pr. F. Garcia-Vidal and Pr. C. Ciuti and it summarizes the actual knowledge on the surprizing implications of the strong coupling regime on matter properties, both on an experimental and theoretical point of view.

(Left) Charge transfer complexation between mesitylene and iodide(courtesy of K. Nagarajan). (Right) Energy transfer between donor and acceptor molecules (courtesy of J. Galego)

We are pleased to announce two new publications.

First, our paper about the enhancement of the ferromagnetism of YBCO nanoparticles under strong-coupling has been accepted in Nano Letters and is now available in open access. Making use of cooperative strong-coupling, we measured a strong ferromagnetism even at room temperature, that competes with superconductivity below the Tc of YBCO. Thanks and congratulations to our collaborators from IPCMS !

Second we published a “Feature Article” in Physics Today, in collaboration with Jérôme Faist from ETH Zürich, dealing with the control of new properties in materials via the hybrid light-matter states created in optical cavities.

To read by the fireside during this rainy and cool spring !

Our latest results have just been accepted for publication in Nature Communications. In this work we strongly couple the exciton of cyanine dye J-aggregates to an optical mode of a Fabry-Perot (FP) cavity, and achieve an enhancement of the complex nonlinear refractive index by two orders of magnitude compared with that of the uncoupled condition. Moreover, the coupled system shows an ultrafast response of ~120 fs that we extract from optical cross-correlation measurements. The ultrafast and large enhancement of the optical nonlinar coefficients in this work paves the way for exploring strong coupling effects on various third-order nonlinear optical phenomena and for technological application. The paper is now accessible in Open Access on Nature Communications website and on our publications page.

Vibrational strong coupling (VSC) has recently been shown to change the rate and chemoselectivity of ground state chemical reactions via the formation of light‐matter hybrid polaritonic states.Our recent observation that vibrational mode symmetry has a large influence on charge transfer reactions under VSC suggested that symmetry considerations could be used to control other types of chemical selectivity. We thus explored the stereoselectivity of the thermal electrocyclic ring‐opening of a cyclobutene derivative, a reaction which follows the Woodward‐Hoffmann rules, under VSC. The direction of the change in stereoselectivity depends on the vibrational mode that is coupled, as do changes in rate and reaction thermodynamics. All this is summarized in a new publication, resulting from a collaboration with Joseph Moran‘s group, that just appeared in Angewandte Chemie in Open Access, but also in our publication page.

An interesting article written by Katrina Krämer just appeared in Chemistry World, about the control of chemical reactions via hybrid-light matter states. It summarizes, via the opinion of some actors of this research field like T.W. Ebbesen, J. Yuen-Zhou or Felipe Herrera, what is known already, what still needs to be understood and what could be the future of the field.

Our latest manuscript has just been accepted for publication in ACS Nano. We are showing that it is possible to enhance both the conductivity and photoconductivity of a p-type semiconductor rr-P3HT that is ultra-strongly coupled to plasmonic modes. In addition, the photoconductivity shows a modified spectral response due to the formation of the hybrid polaritonic states.

Congratulations to all co-authors !